Frost/Freeze in Animas River Basin, Colorado

With eleven of the eighteen reporting stations available for verification recording temperatures at or below 32F for at least 3 hours, at least 50% of the zone experienced a freeze. Only two of the eighteen stations recorded temperatures at or below 28F for at least 3 hours, so this was not a season ending freeze for the zone. The lowest temperature recorded was 26F, while the lowest recorded at the KDRO ASOS in Durango was 28F. Minimum temperatures ranged from 26F to 32F. Temperatures at or below 32F lasted for on average 4 hours, with a maximum of 9 hours and a minimum of 0. Temperatures at or below 28F lasted for on average 1 hour, with a maximum of 5 hours and a minimum of 0.

Cool northwesterly flow set up behind a trough on the 17th. Moisture began to increase during this time, promoting scattered cloud cover. This kept most of the region from reaching freeze criteria overnight, though isolated freezes, none of which were season-ending, did still occur.